///////////////////////////////////////////////////////////////////////////
//                   __                _      _   ________               //
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//                           /____/                                      //
//                                                                       //
//               The Next Generation Logic Library                       //
//                                                                       //
///////////////////////////////////////////////////////////////////////////
//                                                                       //
//  Copyright 2015-20xx Christoph Zengler                                //
//                                                                       //
//  Licensed under the Apache License, Version 2.0 (the "License");      //
//  you may not use this file except in compliance with the License.     //
//  You may obtain a copy of the License at                              //
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//  http://www.apache.org/licenses/LICENSE-2.0                           //
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//  Unless required by applicable law or agreed to in writing, software  //
//  distributed under the License is distributed on an "AS IS" BASIS,    //
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or      //
//  implied.  See the License for the specific language governing        //
//  permissions and limitations under the License.                       //
//                                                                       //
///////////////////////////////////////////////////////////////////////////

package org.logicng.solvers.maxsat.algorithms;

import org.logicng.configurations.Configuration;
import org.logicng.configurations.ConfigurationType;

import java.io.PrintStream;

/**
 * The configuration object for a MaxSAT solver.
 * @version 1.1
 * @since 1.0
 */
public final class MaxSATConfig extends Configuration {

  /**
   * The solver type of the underlying SAT solver.
   */
  public enum SolverType {
    MINISAT, GLUCOSE
  }

  /**
   * The incremental strategy for cardinality and pseudo-boolean constraints.
   */
  public enum IncrementalStrategy {
    NONE, ITERATIVE
  }

  /**
   * The AMO encoding.
   */
  public enum AMOEncoding {
    LADDER
  }

  /**
   * The pseudo Boolean encoding.
   */
  public enum PBEncoding {
    SWC
  }

  /**
   * The cardinality constraint encoding.
   */
  public enum CardinalityEncoding {
    TOTALIZER, MTOTALIZER
  }

  /**
   * The weight strategy.
   */
  public enum WeightStrategy {
    NONE, NORMAL, DIVERSIFY
  }

  /**
   * The verbosity of the solver.
   */
  public enum Verbosity {
    NONE, SOME
  }

  final IncrementalStrategy incrementalStrategy;
  final AMOEncoding amoEncoding;
  final PBEncoding pbEncoding;
  final CardinalityEncoding cardinalityEncoding;
  final WeightStrategy weightStrategy;
  final SolverType solverType;
  final Verbosity verbosity;
  final PrintStream output;
  final boolean symmetry;
  final int limit;
  final boolean bmo;

  /**
   * Constructor for a MaxSAT configuration.
   * @param builder the builder
   */
  private MaxSATConfig(final Builder builder) {
    super(ConfigurationType.MAXSAT);
    this.incrementalStrategy = builder.incrementalStrategy;
    this.amoEncoding = builder.amoEncoding;
    this.pbEncoding = builder.pbEncoding;
    this.cardinalityEncoding = builder.cardinalityEncoding;
    this.weightStrategy = builder.weightStrategy;
    this.solverType = builder.solverType;
    this.verbosity = builder.verbosity;
    this.output = builder.output;
    this.symmetry = builder.symmetry;
    this.limit = builder.limit;
    this.bmo = builder.bmo;
  }

  @Override
  public String toString() {
    final StringBuilder sb = new StringBuilder("MaxSATConfig{").append(System.lineSeparator());
    sb.append("incrementalStrategy=").append(this.incrementalStrategy).append(System.lineSeparator());
    sb.append("pbEncoding=").append(this.amoEncoding).append(System.lineSeparator());
    sb.append("pbEncoding=").append(this.pbEncoding).append(System.lineSeparator());
    sb.append("cardinalityEncoding=").append(this.cardinalityEncoding).append(System.lineSeparator());
    sb.append("weightStrategy=").append(this.weightStrategy).append(System.lineSeparator());
    sb.append("solverType=").append(this.solverType).append(System.lineSeparator());
    sb.append("verbosity=").append(this.verbosity).append(System.lineSeparator());
    sb.append("symmetry=").append(this.symmetry).append(System.lineSeparator());
    sb.append("limit=").append(this.limit).append(System.lineSeparator());
    sb.append("bmo=").append(this.bmo).append(System.lineSeparator());
    sb.append("}").append(System.lineSeparator());
    return sb.toString();
  }

  /**
   * The builder for a MaxSAT configuration.
   */
  public static class Builder {
    private final AMOEncoding amoEncoding;
    private final PBEncoding pbEncoding;
    private IncrementalStrategy incrementalStrategy = IncrementalStrategy.NONE;
    private CardinalityEncoding cardinalityEncoding = CardinalityEncoding.TOTALIZER;
    private WeightStrategy weightStrategy = WeightStrategy.NONE;
    private SolverType solverType = SolverType.GLUCOSE;
    private Verbosity verbosity = Verbosity.NONE;
    private PrintStream output = System.out;
    private boolean symmetry = true;
    private int limit = Integer.MAX_VALUE;
    private boolean bmo = true;

    /**
     * Constructor for the builder.
     */
    public Builder() {
      this.amoEncoding = AMOEncoding.LADDER;
      this.pbEncoding = PBEncoding.SWC;
    }

    /**
     * Sets the incremental strategy. The default value is {@code NONE}.
     * @param inc the incremental strategy
     * @return the builder
     */
    public Builder incremental(final IncrementalStrategy inc) {
      this.incrementalStrategy = inc;
      return this;
    }

    /**
     * Sets the cardinality encoding. The default value is {@code TOTALIZER}.
     * @param card the cardinality encoding
     * @return the builder
     */
    public Builder cardinality(final CardinalityEncoding card) {
      this.cardinalityEncoding = card;
      return this;
    }

    /**
     * Sets the weight strategy. The default value is {@code NONE}.
     * @param weight the weight strategy
     * @return the builder
     */
    public Builder weight(final WeightStrategy weight) {
      this.weightStrategy = weight;
      return this;
    }

    /**
     * Sets the underlying solver type. The default value is {@code GLUCOSE}.
     * @param solver the underlying solver type
     * @return the builder
     */
    public Builder solver(final SolverType solver) {
      this.solverType = solver;
      return this;
    }

    /**
     * Enables symmetry handling. The default value is {@code true}.
     * @param symm {code true} if symmetry handling should be activated, {@code false} otherwise
     * @return the builder
     */
    public Builder symmetry(final boolean symm) {
      this.symmetry = symm;
      return this;
    }

    /**
     * Sets the symmetry limit. The default value is {@code Integer.MAX_VALUE}.
     * @param lim the symmetry limit
     * @return the builder
     */
    public Builder limit(final int lim) {
      this.limit = lim;
      return this;
    }

    /**
     * Enables BMO (Boolean Multilevel Optimization). The default value is {@code true}.
     * @param bmo {code true} if BMO should be activated, {@code false} otherwise
     * @return the builder
     */
    public Builder bmo(final boolean bmo) {
      this.bmo = bmo;
      return this;
    }

    /**
     * Sets the verbosity. The default value is {@code NONE}.  If you set the verbosity to {@code SOME} you have also to
     * set an output stream.
     * @param verb the verbosity level
     * @return the builder
     */
    public Builder verbosity(final Verbosity verb) {
      this.verbosity = verb;
      return this;
    }

    /**
     * Sets the output stream for logging information.  The default ist {@code System.out}.
     * @param output the output stream for logging information
     * @return the builder
     */
    public Builder output(final PrintStream output) {
      this.output = output;
      return this;
    }

    /**
     * Builds the configuration.
     * @return the configuration.
     */
    public MaxSATConfig build() {
      return new MaxSATConfig(this);
    }
  }
}
